A wide variety of absorbent structures designed not only to be efficient for the absorption of body fluids such as blood, urine, menses, and the like, but also to be sanitary and comfortable in-use are known in the literature. Disposable products of this type generally comprise some sort of fluid-permeable topsheet material, an absorbent core, and a fluid-impermeable backsheet material. Various shapes, sizes and thicknesses of such articles have been explored in an attempt to make their use more comfortable and convenient.
One particular aspect of sanitary products which has been under investigation for many years is that of odor control. Many body fluids have an unpleasant odor, or develop such odors when in contact with air and/or bacteria for prolonged periods. The literature is replete with references relating to odor control in products such as diapers and catamenials.
Various odor-controlling agents have been disclosed in the literature. Carbon is well-known for its ability to adsorb odoriferous molecules. Unfortunately, carbon's deep black color makes it unattractive for use in sanitary products, where the white color has become associated in users' minds with cleanliness. Indeed, the drawbacks to the use of activated carbon, including, for example, that activated carbon is black such that the final product does not have an unobtrusive appearance, are noted in EPO 392,528 at page 7. Some attempts have been made to overcome this difficulty by positioning the carbon towards the back of absorbent articles, in the hope that it will be less noticeable. However, any odor-controlling agent is most effective when dispersed throughout the absorbent core or, preferably, close to its fluid-receiving surface. Accordingly, such attempts to "hide" the carbon have met with limited success. Moreover, the manufacturing process for such articles is complicated.
Certain white zeolitic materials are becoming known for their odor-controlling properties. Zeolitic materials are generally quite safe, and while they do effectively control many odors associated with body fluids, it has been determined that, unfortunately, they do not provide optimal control for the broad spectrum of odors that can be controlled by carbon.
Moreover, both carbon and the zeolitic odor-controlling materials tend to be in the form of very small, dusty particles which are difficult to handle on a commercial scale. Such materials tend to be blown or vacuumed up from absorbent structures moving at the high speeds (500-600 items/minute) used on modern catamenial or diaper manufacturing lines.
Accordingly, it would be desirable to provide odor-controlling agents which would control not only the odors such as those the zeolitic materials handle easily, but also a broad spectrum of odors such as those that carbon handles easily. It would also be desirable to provide such agents in a form that is lighter in color, relative to carbon, and which is easy to handle.
The present invention provides a means for safely and effectively overcoming these deficiencies by combining particulate carbon odor-controlling agents with white-colored zeolites or other "masking" materials, using binder materials, as disclosed more fully hereinafter. These and other advantages associated with the present invention will be seen from the disclosure, hereinafter.